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The invention relates to the treatment of and immunization against spontaneous and viral-induced infections, bacterial or parasitic infections, proliferative diseases and inflammatory diseases. More specifically the invention relates to the use of metal chelating materials including, picolinic acid, fusaric acid and their derivatives as chemotherapeutic and/or biological response modifier agents.
It will be appreciated that hereinafter the use of the term xe2x80x9cresponse modiferxe2x80x9d is intended to encompass all of the intended functions of the invention and method including antiviral, antiinfective, antiinflammatory, anticancer, vaccine and so on. Further, it will be appreciated that the broad term xe2x80x9cantiinfectivexe2x80x9d is intended to include antibacterial, antifungal, antiparasitic functions, as well as actions against any other infective agent including viruses not encompassed by the term xe2x80x9cantiviralxe2x80x9d.
Researchers recently have come to appreciate the role of metal containing proteins in proliferative and infectious diseases. Generally speaking, the inventor has studied the important function of proteins having amino acid sequences which bind metals, particularly transition metal ions therein. For example, the inventor has determined the important role zinc finger or zinc ring proteins in proliferative, inflammatory and infectious diseases.
The inventor and others have recognized at least three efficient approaches to inhibiting zinc finger proteins: 1) disruption of the zing finger by modification of the cysteins which are at least one of the four binding sites for Zn2+ in the zinc finger protein which results in the ejection of zinc ion; 2) removal of the zinc from the zinc finger moiety by specific chelating agents; and 3) specific chelating agents that form a ternary complex at the site of zinc binding on zinc finger proteins, resulting in inhibition of the DNA or RNA binding activity of zinc finger proteins.
Papilloma virus infection results in a number of proliferative diseases in subjects including warts induced by type 4 human papilloma virus (common warts). Moreover, papilloma virus can cause plantar ulcers as well as plantar warts. Human papilloma virus infection of the uterine cervix is the most common of all sexually transmitted diseases. Commonly know as genital warts, this wide spread virus infection is a serious disease that potentially can develop into cervical cancer. Since the virus is permanently present in cells, infection recurs in a significant percentage of patients. In many instances, conization of the uterine cervix is required to remove the infected tissue.
Condylomata acuminata, also denoted genital warts, are benign epithelial growths that occur in the genital and perianal areas and caused by a number of human papilloma viruses (HPV) including types 6,11 and 54. These are low risk viruses which rarely progress to malignancy. However, high risk viruses such as HPV-16 and HPV-18 are associated with cervical intraepithelial cancer.
The actions of HPV are mediated by specific viral-encoded proteins which interact and/or modulate cellular DNA and proteins to produce abnormal growth and differentiation of cells. Two proteins of the HPV viral genome, E6 and E7, are well conserved among anogenital HPV""s and both may contribute to the uncontrolled proliferation of basal cells characteristics of the lesions. The E7 oncoprotein is a multi-functional protein with transcriptional modulatory and cellular transforming properties. The E7 oncoprotein is denoted as a xe2x80x9czinc fingerxe2x80x9d protein because it pocesses a sequence motif that is implicated in zinc binding. A strong correlation between zinc binding and the transactivation activity of E7 has been documented. The HPV-16 E6 protein is a xe2x80x9czinc fingerxe2x80x9d protein that binds DNA and may have transcriptional properties such that its function may be dependent upon the formation of zinc fingers. E6 protein can complex with the cellular tumor suppressor protein p53 and it is necessary with E7 protein for the immortalization of primary human squamous cells. Only two proteins of HPV are consistently expressed and integrated in keratinocytes, the E6 and E7 zinc finger proteins. The E6 and E7 proteins are responsible for continuous cell proliferation. About twenty HPVs are associated with ano-genital lesions and all transformed keratinocytes of these lesions contain E6 and E7 zinc finger proteins. The E6 and E7 regulate growth and transformation by interfering with cellular p53 and pRb proteins, respectively. Thus, one should be able to control or cure HPV by inactivating E6 and E7, the critical zinc finger proteins which are required for replication. When replication of the virus is halted, apoptosis of the virally-infected cells must occur. Thus, one can alter the epidemiology of, for example, carcinoma of the uterine cervix by interfering with the function of zinc finger or zinc ring proteins.
The human immunodeficiency virus (HIV) encodes several regulatory proteins that are not found in other retroviruses. The tat protein, which is one of these proteins, trans-activates genes that are expressed from the HIV long terminal repeat and tat is essential for viral replication. The tat protein of the HIV-1 is a zinc finger protein that when added to certain cells in tissue culture, specifically promotes growth. It has been shown that the tat protein of HIV-1 stimulates growth of cells derived from Kaposi""s sarcoma lesions of AIDS patients. Other experiments raised the possibility that tat might act as a viral growth factor to stimulate replication in latently infected cells or alter expression of cellular genes.
The nucleocapsid p7 protein of HIV has been targeted by the inventor for treatment of HIV viral infections. The p7 protein is required for the correct assembly of newly formed virus particles during the viral life cycle. Moreover, the p7 protein contains two zinc fingers that are required for the recognition and packaging of the viral RNA. Because the zinc finger domain is essential for nucleic acid binding, p7 resistant mutants are highly unlikely to occur. Thus, agents that effectively attack the two zinc finger domains of the HIV virus nucleocapsid p7 in vivo will decrease the overall number of viral particles that bud off and exit the cells to infect other cells.
Further, the hepatitis C viruses are dependent upon the Zn 2+ metalloproteinases for specific viral functions.
It is of interest to note that the breast cancer susceptibility gene BRCA 1 includes a zinc ring domain that are involved in protein-protein interactions or protein-DNA interactions. It also is of interest to note that the zinc ring domain of the BRCA 1 has a 54% sequence similarity and 38% sequence identity with a zinc ring domain encoded by the genome of the equine herpes virus. (R. Bienstock, xe2x80x9cMolecular Modeling of Proteins Structures, Science and Medicine, January/Febuary 1997, p.56).
From the foregoing it appears that it would be beneficial to have a product that can interfere with the formation or action of certain zinc finger proteins or zinc ring proteins to stop the progress of certain virally induced or mediated proliferative diseases or to halt the progress of viruses or malignancies dependent upon zinc finger or zinc ring proteins for their transformation and immortalization. Furthermore, it would be beneficial to provide a product that can halt the growth of other proliferative cells, such as malignant cells by chelating metal ions from zinc-dependent or transition metal ion (e.g. copper, iron, etc.) dependent proteins and enzymes necessary for the replication of the malignant cells.
It is among the objects of the present invention to provide a compound which can retard the growth and proliferation of target viruses or cells by blocking the activity of metal ion-containing proteins.
Another object of the present invention to provide a compound which can retard the growth and proliferation of target infective organisms including bacteria, fungi, parasites or other infective agents by blocking the activity of metal ion-containing proteins.
Another object of the present invention is to provide a compound which can retard the growth and proliferation of target viruses or cells by blocking the activity of transition metal ion-containing protein structures such as zinc finger or zinc ring proteins associated with replication.
It is another objects of the present invention to provide a compound that can retard the growth of premalignant and malignant cells such as virally, chemically and spontaneously transformed cells.
It is also among the objects of the present invention to provide a new treatment for patients suffering from various forms of spontaneous and retroviral-induced proliferative diseases and cancers by utilizing the novel properties of metal chelating agents as a chemotherapeutic/anti-viral agent and/or biological response modifier.
It is another object of the present invention to provide an agent that can halt the proliferation and transmission of the HIV virus.
It is another object of the invention to provide a method of halting the function of zinc finger proteins, zinc ring proteins, and other proteins with zinc binding motifs heretofore unidentified by the administration of a zinc chelating agent, both topically and systemically.
Another object of the invention to provide a method of halting the function of metal containing protein structures containing metals other than zinc, metal-containing ring proteins structures, and other proteins with metal binding motifs heretofore unidentified by the administration of a metal chelating agent, both topically and systemically.
Another object of the invention is to provide an antiinflammatory compound that is effective in a broad range of inflammatory disorders including symptoms of well-know autoimmune diseases as well as inflammatory response to infections and to chemical assault or radiation including, but not limited to, ultraviolet, atomic or medical radiation.
Yet another object of the invention is to provide such chelating agents in a relatively safe and nontoxic form such as picolinic acid or its derivatives for both topical and systemic use.
Another object of the invention is to provide a topical preparation of metal chelating agents such as picolinic acid or its derivatives to treat virally induced or spontaneous proliferative diseases of the skin or mucous membranes in human and animal subjects.
It is still another object of the present invention to provide an intravaginal preparation containing metal chelating agents such as picolinic acid or derivatives thereof that can prevent or retard sexually transmitted diseases caused by viruses or other causative agents containing zinc finger proteins or zinc ring proteins.
Still another object of the present invention is to provide a preparation containing chelating agents such as picolinic acid or derivatives thereof that halts the progression of viral infections or proliferative diseases that is non-toxic to normal cells, easy to use, relatively inexpensive and well suited for its intended purposes.
According to the invention, briefly stated, a method or treatment and compound used in the method, for example, metal chelating compounds, such as picolinic acid or derivative thereof, for the treatment of infective or proliferative diseases, actinic lesions, inflammatory response, radiation assault, and cancers in human and animal subjects, as well as the method of treatment. The invention can be used orally or topically to treat or control a wide assortment of proliferative diseases or conditions, both spontaneous or induced by viruses, bacteria, fungi, chemicals, ultraviolet light for example. The metal chelating compounds bind metal, for example iron or transition metal ions such as zinc, required by enzymes, heat shock proteins or by transcription proteins found in viruses or malignant cells. By way of further example, the metal chelating compound, for example picolinic acid or its derivatives, is used to bind the zinc-containing p7 protein common to the HIV virus, thereby inactivating the virus and preventing the exit of RNA containing viruses or particles from the cells.
One embodiment of a topical preparation consists of a solution of the chelator, for example, 0.01% to 99%, preferably 5% to 25%, picolinic acid in deionized water and is applied to the lesion one or two times a day. The preparation can be applied to toe nails and finger nails, for example, to treat fungal infections. In another embodiment, the topical preparation consists of an ointment or cream containing approximately 0.5% to 99%, preferably 5% to 20% picolinic acid which is applied once or twice daily to the lesion and to a bandage placed on the lesion. The ointment or cream can be instilled intravaginally to retard sexually transmitted viral diseases.
The various embodiments of the topical preparation can be used to treat papilloma and herpes viral diseases and to retard the papilloma, herpes and HIV 1 viruses as well as proliferative diseases such as psoriasis, actinic lesions and skin cancer.
Various active derivatives that maintain their activity and stability when after systemic administration are provided. Slow release oral formulations can be used to treat diseases for the digestive tract. The active derivatives can be administered orally, parenterally, by inhalation, transdermally or by any other appropriate method to control proliferative diseases, cancers, viral infections, HIV, and any other condition wherein the causative agent includes a zinc-containing protein, whether the zinc-containing protein is a zinc finger protein, a zinc ring protein, or other type of zinc or metal containing structure heretofore unidentified or undetected, wherein the metal containing segment is required for protein stability and configuration.
It will be appreciated that other appropriate chelating materials such as the derivative of picolinic acid, fusaric acid, also may be used. It also will be appreciated that, although 5% to 20% topical preparations of the picolinic acid are described, a broader range of concentrations may be used. For example from approximately 0.001% to 99.9% metal chelating agent may be used. Further, the systemic doses may be altered or adjusted to ranges greater or lesser than those described, depending on toxicity and patient response, without departing from the scope of the appended claims.